+ mm-vmalloc-make-set_area_direct_map-huge_vmap-friendly.patch added to mm-new branch

+ mm-vmalloc-make-set_area_direct_map-huge_vmap-friendly.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/vmalloc: make set_area_direct_map HUGE_VMAP friendly
has been added to the -mm mm-new branch.  Its filename is
     mm-vmalloc-make-set_area_direct_map-huge_vmap-friendly.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmalloc-make-set_area_direct_map-huge_vmap-friendly.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days

------------------------------------------------------
From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
Subject: mm/vmalloc: make set_area_direct_map HUGE_VMAP friendly
Date: Sun, 23 Aug 2026 14:46:15 +0300

set_area_direct_map() always updates direct map alias permissions in
single page increments.

For HUGE_VMAP areas it's suboptimal.  Not only the loop in
set_area_direct_map() needlessly has more iterations (e.g times 512 on
x86), but it also causes fragmentation of the direct map that could be
avoided for the HUGE_VMAP areas populated with large pages.

All pages in an area are always of the same order: either same-order large
pages when VM_ALLOW_HUGE_VMAP is set and all huge pages were successfully
allocated, or order-0 page when VM_ALLOW_HUGE_VMAP is cleared or when huge
pages allocation fails and fallback path is taken.

Instead of updating the direct map permissions for every order-0 page in
an area, use the area's page_order as the loop increment and update the
large pages in one call to set_direct_map_{invalid,default}_noflush().

Link: https://lore.kernel.org/20260823-execmem-set-vm-perms-v0-2-v2-4-b013a37d84b3@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmalloc.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

--- a/mm/vmalloc.c~mm-vmalloc-make-set_area_direct_map-huge_vmap-friendly
+++ a/mm/vmalloc.c
@@ -3366,12 +3366,15 @@ static inline void set_area_direct_map(c
 				       int (*set_direct_map)(struct page *page,
 							     unsigned int nr))
 {
-	unsigned long i;
+	unsigned int nr = (1U << vm_area_page_order(area));
 
-	/* HUGE_VMALLOC passes small pages to set_direct_map */
-	for (i = 0; i < area->nr_pages; i++)
-		if (page_address(area->pages[i]))
-			set_direct_map(area->pages[i], 1);
+	for (unsigned long i = 0; i < area->nr_pages; i += nr) {
+		if (page_address(area->pages[i])) {
+			int err = set_direct_map(area->pages[i], nr);
+
+			WARN_ON_ONCE(err);
+		}
+	}
 }
 
 /*
_

Patches currently in -mm which might be from rppt@kernel.org are

set_memory-add-number-of-pages-parameter-to-set_direct_map-apis.patch
mm-vmalloc-set-areas-page_order-after-allocation-succeeds.patch
mm-vmalloc-constify-vm-parameter-of-get_vm_area_page_order.patch
mm-vmalloc-make-set_area_direct_map-huge_vmap-friendly.patch
mm-execmem-use-vm_flush_reset_perms-for-rox-cache-allocations.patch
revert-arch-introduce-set_direct_map_valid_noflush.patch
sh-remove-config_numa-and-realted-configuration-options.patch
sh-mm-remove-numac.patch
sh-mm-drop-allocate_pgdat.patch
sh-remove-setup_bootmem_node-and-plat_mem_setup.patch
sh-drop-dead-code-guarded-by-ifdef-config_numa.patch
sh-drop-include-asm-mmzoneh.patch
init-kconfig-drop-arch_want_numa_variable_locality.patch
sh-init-remove-call-the-memblock_set_node.patch
sh-remove-sparsemem-related-entries-from-kconfig.patch
sh-drop-include-asm-sparsememh.patch